Method of Manufacturing Magnetoresistance Effect Element and Apparatus for Manufacturing the Same

ABSTRACT

A method of manufacturing a magnetoresistance effect element having a high MR ratio even with a low RA and an apparatus of the same are provided. The magnetoresistance effect element having an MgO (magnesium oxide) layer provided between a ferromagnetic layer and a second ferromagnetic layer is manufactured by forming a film of the MgO layer in a film forming chamber in which a substance whose getter effect with respect to the oxidizing gas such as oxygen or water is large is adhered to the surfaces of components (an inner wall  37  of a film forming chamber in the interior of a first film forming chamber  21 , inner walls of an adhesion preventing shield  36 , a partitioning plate  22 , a shutter or the like) provided in the chamber for forming the MgO layer. The substance having a large getter effect must simply be a substance whose value of oxygen gas adsorption energy is 145 kcal/mol or higher and, in particular, Ta (tantalum) as a substance which constitutes the magnetoresistance effect element is preferable.

TECHNICAL FIELD

The present invention relates to method of manufacturing amagnetoresistance effect element used for an MRAM (magnetic randomaccess memory) or a magnetic head sensor and an apparatus formanufacturing the same.

BACKGROUND ART

A magnetoresistance effect element is used for an MRAM (magnetic randomaccess memory) or a magnetic head sensor. The magnetoresistance effectelement having a fundamental structure including a first ferromagneticlayer/an insulator layer/a second ferromagnetic layer is, utilizing theproperty such that the electric resistance is low when the direction ofmagnetization of the first ferromagnetic layer and the secondferromagnetic layer extend in parallel and is high when in non-parallel,adapted in such a manner that the direction of magnetization of one ofthe ferromagnetic layers is fixed and the direction of magnetization ofthe other one of the ferromagnetic layers is variable according to theexternal magnetic field to detect the direction of external magneticfield as a change in electric resistance. In order to obtain a highdetection sensitiveness, high MR ratio (magnetoresistance ratio), whichis an index of variation in electric resistance value between the casesin which the direction of magnetization is parallel and non-parallel isrequired. The inventor proposed a magnetoresistance effect element usingmagnesium oxide although referred to as MgO hereinafter, it does notmean that stoichiometry is 1:1) is formed into a film by spattering asan insulator layer of the magnetoresistance effect element as aconfiguration in which a high MR ratio is obtained (for example, seeNon-Patent Document 1 and Patent Document 1).

[Non-Patent Document 1] APPLIED PHYSICS LETTERS 86, 092502 (2005)

[Patent Document 1] Patent Application 2004-259280

DISCLOSURE OF INVENTION Problem to be Solved by the Invention

In order to achieve a higher density of MRAMs or a higher resolution ofmagnetic heads, it is required to further reduce the size of theelement. When the size of the element is reduced, it is necessary toreduce the electric resistance value per 1 μm² (hereinafter, referred toas RA) sufficiently when the direction of magnetization is parallel fora desirable operation. The RA of the magnetoresistance effect element isreduced by reducing the thickness of the MgO film of an insulator layer.However, when the thickness of the MgO film is reduced, the MR ratio issignificantly lowered and, consequently, there arises a problem suchthat both the low RA and the high MR ratio cannot be achievedsimultaneously.

It is an object of the present invention to provide a method ofmanufacturing a magnetoresistance effect element which achieves a highMR ratio even when the value of RA is low, and an apparatus formanufacturing the same.

A method of manufacturing a magnetoresistance effect element accordingto the present invention is a method of manufacturing amagnetoresistance effect element having an MgO layer between a firstferromagnetic layer and a second ferromagnetic layer including a step offorming the first ferromagnetic layer, a step of forming the MgO layer,and a step of forming the second ferromagnetic layer in this order,characterized in that the step of forming the MgO layer is carried outin a film forming chamber including a component having a substance whosegetter effect with respect to oxidizing gas is larger than MgO adheredto the surface thereof.

The method of manufacturing a magnetoresistance effect element accordingto the present invention is characterized in that the film formingchamber for forming the MgO layer includes at least one film formingmeans for a substance whose getter effect with respect to the oxidizinggas is larger than MgO, and adhesion of the substance whose gettereffect with respect to the oxidizing gas is larger than MgO to thecomponent is carried out by one or a plurality of the film formingmeans.

The method of manufacturing a magnetoresistance effect element accordingto the present invention is characterized in that the substance whosegetter effect with respect to the oxidizing gas is larger than MgOincludes at least one element which is included in the substance whichconstitutes the magnetoresistance effect element.

The method of manufacturing a magnetoresistance effect element accordingto the present invention is a method of manufacturing amagnetoresistance effect element having an MgO layer between a firstferromagnetic layer and a second ferromagnetic layer including a step offorming the first ferromagnetic layer, a step of forming the MgO layer,and a step of forming the second ferromagnetic layer in this order,characterized in that the step of forming the MgO layer is carried outin a film forming chamber including a component having a substance whosegetter effect with respect to the oxidizing gas is larger than thesubstance which constitutes the first ferromagnetic layer.

The method of manufacturing a magnetoresistance effect element accordingto the present invention is characterized in that the film formingchamber for forming the MgO layer includes at least one film formingmeans for a substance whose getter effect with respect to the oxidizinggas is larger than the substance which constitutes the firstferromagnetic layer, and adhesion of the substance whose getter effectwith respect to the oxidizing gas is larger than the substance whichconstitutes the first ferromagnetic layer to the component is carriedout by the film forming means.

The method of manufacturing a magnetoresistance effect element accordingto the present invention is characterized in that the substance whosegetter effect with respect to the oxidizing gas is larger than thesubstance which constitutes the first ferromagnetic layer includes atleast one element which is included in the substance which constitutesthe magnetoresistance effect element.

A method of manufacturing a magnetoresistance effect element accordingto the present invention is a method of manufacturing amagnetoresistance effect element having an MgO layer between a firstferromagnetic layer and a second ferromagnetic layer including a step offorming the first ferromagnetic layer, a step of forming the MgO layer,and a step of forming the second ferromagnetic layer in this order,characterized in that the step of forming the MgO layer is carried outin a film forming chamber including a component having a substance whosegetter effect with respect to oxidizing gas is maximum from among thesubstances which constitute the magnetoresistance effect element adheredto the surface thereof.

A method of manufacturing a magnetoresistance effect element accordingto the present invention is a method of manufacturing amagnetoresistance effect element having an MgO layer between a firstferromagnetic layer and a second ferromagnetic layer including a step offorming the first ferromagnetic layer, a step of forming the MgO layer,and a step of forming the second ferromagnetic layer in this order,characterized in that the step of forming the MgO layer is carried outin a film forming chamber including a component having a substance whosevalue of oxygen gas adsorption energy is 145 kcal/mol or higher adheredto the surface thereof.

A method of manufacturing a magnetoresistance effect element accordingto the present invention is a method of manufacturing amagnetoresistance effect element having an MgO layer between a firstferromagnetic layer and a second ferromagnetic layer including a step offorming the first ferromagnetic layer, a step of forming the MgO layer,and a step of forming the second ferromagnetic layer in this order,characterized in that the step of forming the MgO layer is carried outin a film forming chamber having a component including metal or asemiconductor including at least one of Ta (tantalum), Ti (titanium), Mg(magnesium), Zr (zirconium), Nb (niobium), Mo (molybdenum), W(tungsten), Cr (chrome), Mn (manganese), Hf (hafnium), V (vanadium), B(boron), Si (silicon), Al (aluminum) and Ge (germanium) adhered to thesurface thereof.

The method of manufacturing a magnetoresistance effect element accordingto the present invention is characterized in that the step of formingthe MgO layer forms the MgO layer by a spattering method.

A method of manufacturing a magnetoresistance effect element accordingto the present invention is a method of manufacturing amagnetoresistance effect element using an apparatus having a pluralityof film forming chambers including a first film forming chamberconnected to a carrier chamber via a valve being capable of transferringsubstrates through the plurality of film forming chambers withoutimpairing vacuum, including a first step for adhering a substance whosegetter effect with respect to the oxidizing gas is larger than MgO tothe surface of a component in the first film forming chamber, a thirdstep carried out after the first step for forming an MgO layer on thesubstrate in the first film forming chamber, and a second step forcarrying out from a next step of the first step to a step before thethird step in the film forming chamber other than the first film formingchamber, characterized in that the first step, the second step and thethird step are carried out continuously in this order.

A method of manufacturing a magnetoresistance effect element accordingto the present invention is a method of manufacturing amagnetoresistance effect element using an apparatus having a pluralityof film forming chambers including a first film forming chamberconnected to a carrier chamber via a valve being capable of transferringsubstrates through the plurality of film forming chambers withoutimpairing vacuum, including a first step of adhering a substance whosevalue of oxygen gas adsorption energy is 145 kcal/mol or higher to thesurfaces of components in the first film forming chamber, a third stepcarried out after the first step for forming an MgO layer on thesubstrate in the first film forming chamber, and a second step forcarrying out from a next step of the first step to a step before thethird step in the film chamber other than the first film formingchamber, characterized in that the first step, the second step and thethird step are carried out continuously in this order.

A method of manufacturing a magnetoresistance effect element accordingto the present invention is a method of manufacturing amagnetoresistance effect element using an apparatus having a pluralityof film forming chambers including a first film forming chamberconnected to a carrier chamber via a valve being capable of transferringsubstrates through the plurality of film forming chambers withoutimpairing vacuum, including a first step for adhering metal or asemiconductor including at least one of Ta, Ti, Mg, Zr, Nb, Mo, W, Cr,Mn, Hf, V, B, Si, Al and Ge to the surface of a component in the firstfilm forming chamber, a third step carried out after the first step forforming an MgO layer on the substrate in the first film forming chamber,and a second step for carrying out from a next step of the first step toa step before the third step in the film forming chamber other than thefirst film forming chamber, characterized in that the first step, thesecond step and the third step are carried out continuously in thisorder.

The method of manufacturing a magnetoresistance effect element accordingto the present invention is characterized in that the first step adheresthe substance whose getter effect with respect to the oxidizing gas islarge to the surface of the component in the first film forming chamberand, simultaneously, forms a film on the substrate.

The method of manufacturing a magnetoresistance effect element accordingto the present invention is characterized in that the first step iscarried out in parallel with the step of forming a film on the substratein the film forming chamber other than the first film forming chamber.

The method of manufacturing a magnetoresistance effect element accordingto the present invention is characterized in that the third step formsthe MgO layer by a spattering method.

A method of manufacturing a magnetoresistance effect element accordingto the present invention is a method of manufacturing amagnetoresistance effect element using an apparatus having a pluralityof film forming chambers including a first film forming chamberconnected to a carrier chamber via a valve being capable of transferringsubstrates through the plurality of film forming chambers withoutimpairing vacuum, including a step of transferring the substrate to thefirst film forming chamber, spattering Mg in the first film formingchamber and forming an Mg layer on the substrate and, simultaneously,adhering Mg to the surfaces of components in the first film formingchamber, and a subsequent step of forming an MgO layer in the first filmforming chamber.

An apparatus for manufacturing a magnetoresistance effect elementaccording to the present invention is characterized in that a filmforming chamber for forming an MgO layer includes means for adhering asubstance whose getter effect with respect to oxidizing gas is largerthan MgO to the surface of a component in the film forming chamberprovided therein.

An apparatus of manufacturing a magnetoresistance effect elementaccording to the present invention is an apparatus of manufacturing amagnetoresistance effect element having an MgO layer between a firstferromagnetic layer and a second ferromagnetic layer including means foradhering a substance whose getter effect with respect to oxidizing gasis larger than the substance which constitutes a first ferromagneticlayer to the surfaces of components in the film forming chamber in thefilm forming chamber for forming the MgO layer.

The apparatus of manufacturing a magnetoresistance effect elementaccording to the present invention is characterized in that thesubstance whose getter effect with respect to the oxidizing gas is largeis a substance having the largest getter effect with respect to theoxidizing gas in the substances which constitute the magnetoresistanceeffect element.

An apparatus of manufacturing a magnetoresistance effect elementaccording to the present invention includes means for adhering asubstance whose value of oxygen gas adsorption energy is 145 kcal/mol orhigher to the surfaces of components in the film forming chamber in thefilm forming chamber for forming an MgO layer.

An apparatus of manufacturing a magnetoresistance effect elementaccording to the present invention includes means for adhering metal ora semiconductor including at least one of Ta, Ti, Mg, Zr, Nb, Mo, W, Cr,Mn, Hf, V, B, Si, Al and Ge to the surface of the component in the filmforming chamber in the film forming chamber for forming an MgO layer.

The apparatus of manufacturing a magnetoresistance effect element in thepresent invention has a plurality of film forming chambers including thefilm forming chamber connected to a carrier chamber for forming the MgOlayer via a valve being capable of transferring substrates through theplurality of film forming chambers without impairing vacuum.

The apparatus of manufacturing a magnetoresistance effect elementaccording to the present invention is characterized in that a target ofMgO is provided in the film forming chamber for forming the MgO layer,and an electric power supply unit for supplying an electric power to thetarget is provided.

A method of manufacturing a magnetoresistance effect element accordingto the present invention is a method of manufacturing amagnetoresistance effect element having an MgO layer between a firstferromagnetic layer and a second ferromagnetic layer, including a stepof forming the first ferromagnetic layer, a step of forming the MgOlayer, and a step of forming the second ferromagnetic layer,characterized in that the step of forming the MgO layer is carried outin a state in which a substrate is at a floating potential.

A method of manufacturing a magnetoresistance effect element accordingto the present invention is a method of manufacturing amagnetoresistance effect element having a substrate, a firstferromagnetic layer, a second ferromagnetic layer and an MgO layerformed between the first ferromagnetic layer and the secondferromagnetic layer, including a step of forming the first ferromagneticlayer on the substrate, a step of forming the MgO layer, and a step offorming the second ferromagnetic layer, characterized in that the stepof forming the MgO layer is carried out by placing the substrate on asubstrate placing bed having a portion which comes into contact with thesubstrate formed of an insulating substance.

The method of manufacturing a magnetoresistance effect element accordingto the present invention is characterized in that the substrate isplaced on the substrate placing bed on which the insulating substance issprayed.

The method of manufacturing a magnetoresistance effect element accordingto the present invention is characterized in that the substrate isplaced on the substrate placing bed formed of the insulating substance.

The method of manufacturing a magnetoresistance effect element accordingto the present invention is characterized in that the step of formingthe MgO layer is carried out in a state in which a mask is arranged on aperipheral portion of the substrate so as to be apart from thesubstrate.

A method of manufacturing a magnetoresistance effect element accordingto the present invention is a method of manufacturing amagnetoresistance effect element having an MgO layer between a firstferromagnetic layer and a second ferromagnetic layer, including a stepof forming the first ferromagnetic layer, a step of forming the MgOlayer and a step of forming the second ferromagnetic layer,characterized in that the step of forming the MgO layer is carried outin a state in which the substrate and a substrate holding holder forholding the substrate are electrically insulated.

The method of manufacturing a magnetoresistance effect element accordingto the present invention is characterized in that the step of formingthe MgO layer is carried out in a state in which a mask electricallyinsulated from the substrate is arranged in the peripheral portion ofthe substrate.

An apparatus for manufacturing a magnetoresistance effect elementaccording to the present invention is an apparatus of manufacturing amagnetoresistance effect element having an MgO layer between a firstferromagnetic layer and a second ferromagnetic layer including means forbringing a substrate into a state of being at a floating potential in afilm forming chamber for forming the MgO layer.

An apparatus of manufacturing a magnetoresistance effect elementaccording to the present invention is an apparatus of manufacturing amagnetoresistance effect element having an MgO layer between a firstferromagnetic layer and a second ferromagnetic layer including means forelectrically insulating a substrate and a substrate holder for holdingthe substrate in a film forming chamber for forming the MgO layer.

ADVANTAGES OF THE INVENTION

In the method of manufacturing a magnetoresistance effect element andthe apparatus for manufacturing the same according to the presentinvention, the MgO layer is formed on the substrate in a state in whichthe substance whose getter effect with respect to oxygen or water or thelike (hereinafter, referred to as oxidizing gas) is large is adhered tothe surface of the component in the film forming chamber for forming theMgO layer. Accordingly, even when the thickness of the MgO film issmall, the magnetoresistance effect element with a high MR ratio isobtained and, consequently, the magnetoresistance effect element at ahigh MR ratio is obtained with a low value of RA. It is considered thatthe oxidizing gas such as oxygen or water discharged from the filmforming means during formation of the MgO layer is taken by thesubstance whose getter effect with respect to the oxidizing gas such asoxygen or water is large and hence is removed, so that the MgO layer isformed in a state in which not much residual gas exists in the filmforming chamber.

By selecting the substance whose getter effect with respect to theoxidizing gas such as oxygen or water is large, which is to be adheredto the interior of an MgO film forming chamber, from among thesubstances which constitutes the magnetoresistance effect element as atarget, means for adhering the substance whose getter effect withrespect to the oxidizing gas such as oxygen or water is large to thesurface of the component in the MgO film forming chamber and means forforming a thin layer may be commonly used, so that it is not necessaryto provide specific means for adhering the substance whose getter effectwith respect to the oxidizing gas such as oxygen or water is large.Since the step of adhering the substance whose getter effect withrespect to the oxidizing gas such as oxygen or water is large to thesurface of the component in the MgO film forming chamber and a step offorming the thin layer are achieved simultaneously, the steps may bereduced.

After having studied in various manner, it was found that the step offorming the MgO insulator layer is important from among the thin layerswhich constitute the magnetoresistance effect element, and the propertyof the magnetoresistance effect element is significantly affected by thetype of the substance adhered to the surface of the component in thefilm forming chamber for forming the MgO insulator layer.

Also, after having studied, it was found that when the substance adheredto the surface of the component in the film forming chamber is thesubstance whose getter effect with respect to the oxidizing gas such asoxygen or water is large, the magnetoresistance effect element at a highMR ratio is obtained even with the low value of RA. The presentinvention is achieved on the basis of the knowledge as described above.

In the method of manufacturing a magnetoresistance effect element andthe apparatus for manufacturing the same, the MgO layer is formed in thestate in which the substrate is at the floating potential, or in thestate in which the substrate and the substrate holder for holding thesubstrate are electrically insulated, so that the magnetoresistanceeffect element at the high MR ratio is obtained even though thethickness of the MgO film is small and, consequently, themagnetoresistance effect element at the high MR ratio was obtained evenwith the low value of RA.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a drawing showing an example of a thin film configuration of amagnetoresistance effect element having an MgO insulator layer, which ismanufactured in a first embodiment of the present invention.

FIG. 2 is a plane pattern diagram showing an example of a configurationof a film forming chamber in a manufacturing apparatus according to thefirst embodiment of the present invention.

FIG. 3 is a cross-sectional view for explaining an internalconfiguration of a first film forming chamber in the manufacturingapparatus shown in FIG. 2.

FIG. 4 is a drawing showing a result of comparison of film thickness/MRratio characteristics of the MgO layer of the magnetoresistance effectelement between the manufacturing method according to the presentinvention and the manufacturing method in the related art.

FIG. 5 is a drawing showing a result of comparison of RA/MR ratiocharacteristics of the MgO layer of the magnetoresistance effect elementbetween the manufacturing method according to the present invention andthe manufacturing method in the related art.

FIG. 6 is a drawing showing an example of a thin film configuration ofthe magnetoresistance effect element having the MgO insulator layermanufactured in the second embodiment of the present invention.

FIG. 7 is a plane pattern diagram showing an example of a configurationof the film forming chamber of a manufacturing apparatus used in thesecond embodiment of the present invention.

FIG. 8 is a drawing showing an example of the thin film configuration ofthe magnetoresistance effect element having the MgO insulator layerwhich is manufactured in the third embodiment of the present invention.

FIG. 9 is a plane pattern diagram showing an example of a configurationof the film forming chamber of a manufacturing apparatus used in thethird embodiment of the present invention.

FIG. 10 is a drawing showing a result of comparison of measured MRratios of the magnetoresistance effect elements obtained by forming theMgO layer on the substrates 12 having the configuration shown in FIG. 1in a state in which various substances are adhered to the surfaces ofthe components in the first film forming chamber for forming the MgOlayer right before forming the MgO layer on the substrates 12.

FIG. 11 is a drawing showing an example of the thin film configurationof the magnetoresistance effect element having the MgO layer which ismanufactured in the fifth embodiment of the present invention.

FIG. 12 is a cross-sectional view for explaining the internalconfiguration of the first film forming chamber in the manufacturingapparatus in the fourth embodiment of the present invention.

FIG. 13 is a drawing showing RA/MR ratio characteristics of the MgOlayer of the magnetoresistance effect element according to the fourthembodiment of the present invention.

FIG. 14 is a cross-sectional view for explaining the internal structureof the first film forming chamber of the manufacturing apparatus in thesixth embodiment of the present invention.

FIG. 15A and FIG. 15B are drawings showing a configuration of theportion near the substrate holder in the manufacturing apparatus in theseventh embodiment of the present invention. FIG. 15A is a drawingshowing a state, and in which a mask and the substrate is in contactwith each other. FIG. 15B is a drawing showing a state in which the maskand the substrate are apart from each other.

FIG. 16 is a drawing showing the RA/MR ratio characteristic of the MgOlayer of the magnetoresistance effect element according to seventhembodiment of the present invention.

REFERENCE NUMERALS

-   -   2 first ferromagnetic layer    -   3 second ferromagnetic layer    -   4 MgO layer    -   5 Ru layer    -   6 CoFe layer    -   8 antiferromagnetic layer (PtMn)    -   9 lower electrode layer    -   10 upper electrode layer    -   10 a upper electrode layer (Ta)    -   10 b upper electrode layer (Ta)    -   10 c upper electrode layer (Cu)    -   11 antioxidant layer    -   12, 120 substrate    -   21 first film forming chamber    -   22 partitioning plate    -   23 target mounting portion    -   24 target (MgO)    -   25 target mounting portion    -   26 target (Ta)    -   27, 28 shutter    -   29 substrate holder    -   31 shutter    -   34 valve    -   35 vacuum exhausting means    -   36 adhesion preventing shield    -   37 film forming chamber inner wall    -   41 second film forming chamber    -   42 third film forming chamber    -   43 carrier chamber    -   44 load lock chamber    -   45 unload lock chamber    -   46 first Ta film forming means    -   47 MgO film forming means    -   48 PtMn film forming means    -   49 CoFe film forming means    -   50 Ta film forming means    -   51 Ru film forming means    -   52 CoFeB film forming means    -   61 a first Ta layer    -   61 b second Ta layer    -   62 CuN layer    -   62 a first CuN layer    -   62 b second CuN layer    -   64, 640 lower electrode layer    -   65 CuN film forming means    -   66 Mg layer    -   67 Mg film forming means    -   68 ground layer (Ta)    -   69 ground layer (Ru)    -   80 antiferromagnetic layer (IrMn)    -   290 substrate placing bed    -   295 mask

BEST MODE FOR CARRYING OUT THE INVENTION

Referring now to FIG. 1, FIG. 2 and FIG. 3, a first embodiment of thepresent invention will be described. FIG. 1 is a drawing showing anexample of a configuration of a thin film of a magnetoresistance effectelement having an MgO insulator layer, which is manufactured in thefirst embodiment.

In FIG. 1, on an Si (silicon) substrate 12 formed with SiO₂ (silicondioxide) on the surface thereof, a lower electrode layer 9 (filmthickness: 10 nm) formed of Ta (tantalum), a PtMn (platinum manganese)antiferromagnetic layer 8 (film thickness: 15 nm) formed of PtMn(platinum manganese), a CoFe (cobalt iron) layer 6 (film thickness: 2.5nm), an Ru (ruthenium) layer 5 (film thickness: 0.85 nm), a firstferromagnetic layer 2 (film thickness: 3 nm) formed of CoFeB (cobaltiron boron), MgO layer 4 (film thickness: 1.0 nm) formed of MgO(magnesium oxide), a second ferromagnetic layer 3 (film thickness: 3 nm)formed of CoFeB, an upper electrode layer 10 (film thickness: 10 nm)formed of Ta, and an Ru layer 11 (film thickness: 7 nm) for preventingoxidation are laminated.

Referring now to FIG. 2, a manufacturing apparatus according to thepresent invention will be described. FIG. 2 is a plane pattern diagramshowing an example of a configuration of a film forming chamber in themanufacturing apparatus according to the first embodiment of the presentinvention, including a carrier chamber 43, a load lock chamber 44,unload lock chamber 45, a first film forming chamber 21, a second filmforming chamber 41 and a third film forming chamber 42 which are eachable to exhaust air to a vacuum state. The load lock chamber 44 and theunload lock chamber 45 are connected to the carrier chamber 43 viavalves, whereby substrates may be transferred between an outer space atan atmospheric pressure and the interior of the vacuum apparatus. Thefirst film forming chamber 21, the second film forming chamber 41 andthe third film forming chamber 42 are connected to the carrier chamber43 via the valves. Accordingly, mutual transfer among the respectivefilm forming chambers is achieved while maintaining the vacuum state.

The each film forming chamber include film forming means for forming therespective layers described above of the magnetoresistance effectelement. In other words, the first film forming chamber 21 is providedwith first Ta film forming means 46 and MgO film forming means 47, thesecond film forming chamber 41 is provided with PtMn film forming means48, CoFe film forming means 49 and second Ta film forming means 50, andthe third film forming chamber 42 is provided with an Ru film formingmeans 51 and CoFeB film forming means 52. The substrates are transferredthrough the respective film forming chambers without being exposed to anatmosphere, and are each formed with films in sequence by the filmforming means which forms the respective layers of the magnetoresistanceeffect element.

FIG. 3 is a cross-sectional view for explaining an internalconfiguration of the first film forming chamber in the manufacturingapparatus shown in FIG. 2. The internal configurations of the secondfilm forming chamber and the third film forming chamber are the same asthe first film forming chamber other than that films of differentsubstances are formed respectively. The film forming means in thisembodiment employs a spattering method. The first film forming chamber21 is connected to a carrier chamber via a valve 34, and air-tightnessin the interior thereof is maintained by closing the valve 34. The firstfilm forming chamber 21 is provided with a substrate holder 29 forholding a substrate 12 on the lower portion thereof. The surface of thesubstrate holder 29 is covered with an insulator formed of aluminumnitride.

The film forming means each include a target as a film forming substanceand a power supply unit for the target as principal elements. In theupper portion of the first film forming chamber 21, a target 24 formedof MgO is attached to a target mounting portion 23. Also, a target 26formed of Ta is attached to a target mounting portion 25 by beingpartitioned by a partitioning plate 22. The target 24 (MgO) and thetarget 26 (Ta) receive a supply of high-frequency power from ahigh-frequency power source (not shown in the drawing) via the targetmounting portions 23, 25.

A shutter 27 for shielding the target 24 (MgO) and a shutter 28 forshielding the target 26 (Ta) are provided, and the substrate 12 isshielded by a shutter 31. The shutters 27, 28, 31 are each adapted to beretracted individually from positions shown in the drawing according tothe spattering of the target 24 (MgO) or the target 26 (Ta). The firstfilm forming chamber 21 is provided with a cylindrical adhesionpreventing shield 36 so as to cover the side surface of a film formingchamber inner wall 37. The film forming chamber inner wall, the adhesionpreventing shield, the shutters, the partitioning plate or the like arereferred to as components, hereinafter.

The first film forming chamber 21 is provided at the lower portionthereof with a vacuum exhausting means 35 for exhausting air from thefilm forming chamber 21 and bringing the interior thereof into a vacuumstate.

Referring now to FIG. 2, a method of carrying out the film formingprocess to form the magnetoresistance effect element as an example shownin FIG. 1 according to the first embodiment of the invention will bedescribed.

The Si (silicon) substrate 12 formed with SiO₂ (silicone dioxide) iscarried into the first film forming chamber 21 for forming the film ofthe lower electrode layer 9 formed of Ta, and is held by the holder 29.The surface of the holder 29 is covered with an insulating substanceformed of aluminum nitride, and the substrate 12 is held in anelectrically floating state. Air is exhausted from the first filmforming chamber 21 to a pressure lower than a background pressure 10⁻⁷Pa before the film formation, Ar (argon) is introduced into the firstfilm forming chamber 21, the pressure therein is adjusted to apredetermined pressure, the shutter 27, the shutter 28 and the shutter31 are brought into a closed state, a high-frequency power is applied tothe Ta target 26, and a pre-spattering process of Ta is carried out.Subsequently, the shutter 31 and the shutter 28 are brought into anopened state, and a high-frequency power is applied to the Ta target 26to form a Ta film on the substrate 12. Simultaneously with this, thefilm forming chamber inner wall 37, the inner walls of the adhesionpreventing shield 36, the partitioning plate 22 or the shutters or thelike as the components in the interior of the first film forming chamber21 are partly covered with Ta spattered from the Ta target 26. The areasin which spatter particles are adhered from the Ta target are differentdepending on the position or the shape of the target, the position orthe shape of the components in the film forming chamber, and the filmforming conditions. After having spattered for a predetermined timeperiod, the shutter 31 is brought into a closed state, and thehigh-frequency power to be applied to the Ta target 26 is turned off.

The substrate 12 formed with the Ta lower electrode layer 9 is carriedout from the first film forming chamber 21, and is transferred to thesecond film forming chamber 41 provided with the PtMn film forming means48 and the CoFe film forming means 49, and held by the holder. The PtMnlayer 8 is formed on the substrate using the PtMn film forming means 48,and then the CoFe layer 6 is formed using the CoFe film forming means49. Subsequently, the substrate 12 is carried out from the second filmforming chamber 41, is transferred to the third film forming chamber 42provided with the Ru film forming means 51 and the CoFeB film formingmeans 52, and held by the holder. The Ru layer 5 is formed on thesubstrate using the Ru film forming means 51, and then the CoFeBferromagnetic layer 2 formed of CoFeB is formed using the CoFeB filmforming means 52. In this manner, the PtMn antiferromagnetic layer 8,the CoFe antiferromagnetic layer 6, the Ru layer 5 and the firstferromagnetic layer 2 shown in FIG. 1 are formed in sequence. Thebackground pressure in the respective film forming chambers before filmformation is 10⁻⁷ Pa or lower.

The substrate 12 having the layers up to the first ferromagnetic layer 2laminated thereon in FIG. 1 is carried into the first film formingchamber 21 again for forming next the MgO layer 4 and held by thesubstrate holder 29. At this time, the surfaces of the components in thefirst film forming chamber 21 are adhered on top thereof with Ta whichhas spattered in the step of forming the Ta layer on the substrate. Inthe film forming chamber in this state, a film of the MgO layer isformed by spattering on the substrate 12. An MgO pre-spattering processis carried out by bringing the shutter 28, the shutter 27 and theshutter 31 in the closed state and applying a high-frequency power tothe MgO target 24. Then, the shutter 27 is brought into an opened state,and MgO is spattered for a predetermined time period. Then, the shutter31 is brought into an opened state, and the MgO layer 4 is formed on thesubstrate 12.

The substrate 12 is carried out from the first film forming chamber 21,and is moved to the third film forming chamber 42 provided with theCoFeB film forming means 52, where the second ferromagnetic layer 3formed of CoFeB is formed. Subsequently, the substrate 12 is carriedinto the first film forming chamber 21 again where the first Ta filmforming means 46 is arranged, where the Ta upper electrode layer 10 isformed thereon. Subsequently, the substrate 12 is moved to the thirdfilm forming chamber 42 where the Ru film forming means 51 is provided,where the Ru antioxidant layer 11 is formed. The magnetoresistanceeffect element shown in FIG. 1 thus formed demonstrates a preferableperformance having a high MR ratio even though the thickness of the filmlayer of the MgO is small. Consequently, the magnetoresistance effectelement with a high MR ratio is obtained even with a low value of RA.

In the first embodiment of the present invention, the film forming meansfor the substance whose getter effect with respect to the oxidizing gasis the largest (Ta in this embodiment) from among the substances whichconstitute the magnetoresistance effect element is provided in the firstfilm forming chamber provided with the film forming means for MgO, sothat only the film of the substance whose getter effect with respect tothe oxidizing gas is the largest (Ta in this embodiment) from among thesubstances which constitute the magnetoresistance effect element and theMgO film are formed in the first film forming chamber for forming theMgO film. The getter effect of Ta to be adhered to the surface of thecomponents in the film forming chamber for forming the MgO layer withrespect to the oxidizing gas is higher than the getter effect of MgO orCoFeB for forming the first ferromagnetic layer with respect to theoxidizing gas.

FIG. 4 is a drawing showing a result of comparison of the filmthickness/MR ratio characteristics of the MgO layer of themagnetoresistance effect element between the manufacturing methodaccording to the present invention and the manufacturing method in therelated art, and FIG. 5 is a drawing of comparison of the RA/MR ratiocharacteristic of the MgO layer of the magnetoresistance effect elementbetween the manufacturing method according to the present invention andthe manufacturing method in the related art. In the method in therelated art, the Ta lower electrode layer and the Ta upper electrodelayer are formed using the second Ta film forming means 50 provided inthe second film forming chamber 41. In the method in the related art,the MgO layer is formed in the film forming chamber in which MgO isadhered to the surfaces of the components in the first film formingchamber for forming the MgO layer.

In FIG. 4, the MgO film thickness/MR ratio characteristic of themagnetoresistance effect element manufactured in the manufacturingmethod in the present invention in which the MgO layer is formed in thefilm forming chamber to which Ta is adhered is represented by hollowsquares (□) and the MgO film thickness/MR ratio characteristic of themagnetoresistance effect element manufactured in the manufacturingmethod in the related art in which the MgO layer is formed withoutadhesion of Ta is represented by solid diamonds (♦). While the MR ratiowas lowered with reduction of the film thickness of the MgO layer in themanufacturing method in the related art, the magnetoresistance effectelement with a high MR ratio was obtained even when the film thicknessof the MgO layer was reduced to 0.9 nm according to the manufacturingmethod in the present invention.

In FIG. 5 as well, the RA/MR ratio characteristic of themagnetoresistance effect element manufactured in the manufacturingmethod in the present invention is represented by hollow squares (□) andthe RA/MR ratio characteristic of the magnetoresistance effect elementmanufactured in the manufacturing method in the related art isrepresented by solid diamonds (♦). While the MR ratio when the RA isabout 150 Ωμm² does not reach 50% in the manufacturing method in therelated art, the MR ratio when the RA is about 2 Ωμm² reaches about 130%according to the manufacturing method in the present invention, so thatthe magnetoresistance effect element with a high MR ratio was obtainedwith a low value of RA.

According to the first embodiment of the present invention, it isconsidered that since the surfaces of the components in the film formingchamber when forming the film of MgO were covered with Ta which providesa larger getter effect with respect to the oxidizing gas discharged whenforming the MgO film so as to have a high getter effect with respect tothe oxidizing gas discharged when forming the MgO film, oxidation of thesurface of the ferromagnetic layer 2 and deterioration of the formedfilm quality of the MgO layer 4 were prevented.

In both of the manufacturing method in the related art and themanufacturing method in the present invention, the respective thin filmlayers of the magnetoresistance effect element were formed in the filmforming chamber which was exhausted into a vacuum state with abackground pressure of 10⁻⁷ or lower Pa. Without adhering Ta which is asubstance whose getter effect with respect to the oxidizing gas is largeto the surfaces of the components in the MgO film forming chamber,lowering of the MR ratio when the thickness of the MgO film is small wasnot improved even when the magnetoresistance effect element was formedby setting the background pressure to 10⁻⁷ Pa and forming the MgOinsulator layer. MgO is a substance of sodium monoxide which easilyadsorb water, and the sintered compact of MgO is porous substance, sothat it is considered that the oxidizing gas such as oxygen or water isadsorbed to the MgO target. Even when the background pressure isadjusted to 10⁻⁷ Pa by exhausting air, the oxidizing gas adsorbed to thetarget cannot be exhausted easily, and the oxidizing gas is dischargedinto a film forming space during MgO film formation from the MgO targetwhich is shocked by ion simultaneously with the start of spattering ofMgO. Therefore, it is considered that oxidation of the surface of theferromagnetic layer formed on the substrate to be processed ordeterioration of the film quality of the MgO insulator layer to beformed are resulted, so that the characteristics of themagnetoresistance effect element are deteriorated.

The substance whose getter effect with respect to the oxidizing gas suchas oxygen or water is large is not limited to Ta, and Ti, Mg, Zr, Nb,Mo, W, Cr, Mn, Hf, V, B, Si, Al and Ge may also be applicable. An alloyformed of two or more substances whose getter effects with respect tothe oxidizing gas are large is also be possible.

In the embodiment described above, since the substance whose gettereffect with respect to the oxidizing gas is large to be adhered to theinterior of the MgO film forming chamber, the same substance (Ta) wasselected for the lower electrode layer 9 and the upper electrode layer10 which constitute the magnetoresistance effect element, a method ofadhering the substance whose getter effect with respect to the oxidizinggas is large (Ta) in the MgO film forming chamber is achievedsimultaneously with the film forming steps for Ta the lower electrodelayer 9 and the Ta upper electrode layer 10, and hence provision of thespecific steps for that is not necessary. Also, since Ta on the Ta lowerelectrode layer 9 and on the upper electrode layer 10 which constitutethe magnetoresistance effect element is formed in the first film formingchamber 21 for forming a film of MgO in the first embodiment, Ta may beadhered relatively thickly and over a wide range to the MgO film formingchamber, so that a large getter effect is achieved.

Furthermore, in the first embodiment, it is also possible to insert astep of adhering Ta to the surface of the components in the first filmforming chamber 21 just before forming the MgO layer 4. By insertingsuch the step, Ta is adhered in addition to Ta which is adhered to thesurface of the components in the first film forming chamber 21 in thestep of forming the Ta layer which constitutes the magnetoresistanceeffect element, so that the thickness of Ta to be adhered to the surfaceof the components in the first film forming chamber 21 and the area toadhere Ta may be increased. In addition, since the Ta may be adhered tothe interior of the film forming chamber just before the step of formingthe MgO layer, it is considered that a high getter effect is achievedwith respect to the oxidizing gas discharged when forming the MgO film.

When the substrate 12 is out of the first film forming chamber 21 (forexample, during the film forming process of the first ferromagneticlayer 2), it is also possible to carry out a step of adhering Ta to thesurfaces of the components in the first film forming chamber 21 byspattering Ta with the shutter 31 in the closed state using the Ta filmforming means provided in the first film forming chamber 21.Accordingly, the thickness of Ta to be adhered to the surfaces of thecomponents in the first film forming chamber 21 may be increased, andthe area to be adhered may be increased. Therefore, the getter effectwith respect to the oxidizing gas to be discharged when forming the MgOfilm may be increased. In addition, since this step is carried out inparallel with the film forming step on the substrate, it has anadvantage that it is not necessary to increase the process time. Thespattering step for adhering Ta to the surfaces of the components in thefirst film forming chamber 21 may be carried out by placing a dummysubstrate on the substrate holder instead of operation to bring theshutter 31 into the closed state.

Referring now to FIG. 6 and FIG. 7, a second embodiment will bedescribed.

FIG. 6 is a drawing showing an example of a configuration of a thin filmof the magnetoresistance effect element having the MgO insulator layeraccording to the second embodiment of the present invention. Instead ofthe lower electrode layer 9 in FIG. 1, a lower electrode portion 64 isformed in FIG. 6. The lower electrode portion 64 includes a first Talayer 61 a, a CuN layer 62, and a second Ta layer 61 b. The thin filmstructures of other portions of the magnetoresistance effect element arethe same as those in FIG. 1 according to the first embodiment.

FIG. 7 is a schematic diagram of a manufacturing apparatus used in thesecond embodiment of the present invention. In FIG. 7, a CuN filmforming means 65 is newly provided in the first film forming chamber inthe manufacturing apparatus in FIG. 2 which is used in the firstembodiment. In other words, as a characteristic of the manufacturingapparatus in the second embodiment, film forming means of a substancewhose getter effect with respect to the oxidizing gas is large (Ta) andfilm forming means of a substance whose getter effect with respect tothe oxidizing gas is small (CuN) are both provided in the first filmforming chamber having the film forming means for forming the film ofMgO.

Referring now to FIG. 6 and FIG. 7, an example of the magnetoresistanceeffect element regarding a method of film forming process according tothe second embodiment of the manufacturing apparatus and themanufacturing method of the present invention.

As regards the Si substrate 12 formed with the SiO₂ film, the filmformation is carried out in the first film forming chamber 21 in whichthe first Ta film forming means 46 is provided in order to form the filmof the first Ta layer 61 a of the lower electrode portion 64 (see FIG.6). At the same time, Ta is adhered to part of the surfaces of the filmforming chamber inner wall 37, the adhesion preventing shield 36, thepartitioning plate 22 and the shutters or the like, which are thecomponents in the first film forming chamber 21. Subsequently, using theCuN layer 62 provided in the first film forming chamber 21, the CuNlayer 62 of the lower electrode portion 64 is formed (see FIG. 6).Simultaneously, spattered CuN is adhered to the interior of the firstfilm forming chamber 21. Subsequently, using the first Ta film formingmeans 46 provided in the first film forming chamber 21, a film of Ta isformed on the substrate 12 in order to form the second Ta layer 61 b ofthe lower electrode portion 64 (see FIG. 6). Simultaneously, Ta as thesubstance whose getter effect with respect to the oxidizing gas is largeis adhered to the outermost surface of the components in the first filmforming chamber 21. Subsequently, the substrate 12 formed with the Talower electrode portion 64 is carried out from the first film formingchamber 21, is moved through the second film forming chamber 41 providedwith the respective film forming means for PtMn and CoFe, the third filmforming chamber 42 provided with the respective film forming means of Ruand CoFeB in sequence, and the PtMn antiferromagnetic layer 8, the CoFelayer 6, the Ru layer 5 and the first ferromagnetic layer 2 formed ofCoFeB are formed in sequence as in the first embodiment. The backgroundpressures in the respective film forming chambers before film formationis 10⁻⁷ Pa or lower.

Then, the substrate 12 is carried into the first film forming chamber21, and the MgO film is spattered by the MgO film forming means 47. Whenforming the MgO layer 4, the interior of the first film forming chamber21 is in a state in which Ta whose getter effect with respect to theoxidizing gas is large is adhered to the surface thereof.

Then, the substrate 12 formed with layers up to the MgO layer 4 moves tothe third film forming chamber 42 in which the CoFeB film forming meansis provided, where the second ferromagnetic layer 3 formed of CoFeB isformed thereon. In order to form the upper electrode layer 10, thesubstrate 12 is carried again to the first film forming chamber 21,where the film of Ta is formed on the substrate by the first Ta filmforming means. Finally, the substrate is moved to the third film formingchamber 42, and the Ru layer 11 is formed by the Ru film forming means51, and the magnetoresistance effect element having the thin filmstructure shown in FIG. 6 is formed.

In the second embodiment of the present invention, both the film formingmeans for the substance whose getter effect with respect to theoxidizing gas is the largest (Ta in this embodiment) from among thesubstances which form the thin film layer which constitute themagnetoresistance effect element in this embodiment and the film formingmeans for the substance whose getter effect with respect to theoxidizing gas is small (CuN in this embodiment) from among the same areprovided in the first film forming chamber for forming the film of MgO.Then, after having adhered the substance whose getter effect withrespect to the oxidizing gas is small to the surface of the componentsin the first film forming chamber, the substance whose getter effectwith respect to the oxidizing gas is large is adhered thereto, and thenthe MgO film is formed in a state in which the substance whose gettereffect with respect to the oxidizing gas is large is adhered to theinterior of the first film forming chamber.

The magnetoresistance effect element shown in FIG. 6 formed in thismanner demonstrated a preferable performance having a high MR ratio eventhough the thickness of the film of the MgO layer was small.Consequently, the magnetoresistance effect element with a high MR ratiowas obtained even with a low value of RA. In addition, since the firstTa layer, the CuN layer and the second Ta layer could be formedcontinuously in the one film forming chamber, the substrate could becarried simply, and the process time may be reduced.

The second embodiment of the present invention includes the film formingmeans for the substance whose getter effect with respect to theoxidizing gas is small and means for adhering the substance whose gettereffect with respect to the oxidizing gas is large to the surfaces of thecomponents in the first film forming chamber for forming the MgO layer,and includes a step of adhering the substance whose getter effect withrespect to the oxidizing gas is large (Ta in this embodiment) to thesurface of the components in the film forming chamber before forming thefilm of MgO so that the substance whose getter effect with respect tothe oxidizing gas is large is adhered to the surface of the componentsin the film forming chamber after the substance whose getter effect withrespect to the oxidizing gas is small is adhered right before formingthe MgO layer.

In the second embodiment of the present invention, the film formingmeans for the MgO film, the film forming means for Ta and the filmforming means for CuN are provided in the film forming chamber forforming the MgO layer. Ta has the highest getter effect with respect tothe oxidizing gas from among the substances to be adhered by the filmforming means. Also, the getter effect of Ta to be adhered to thesurfaces of the components in the film forming chamber for forming theMgO layer with respect to the oxidizing gas is larger than the gettereffect of the CoFeB which constitutes MgO or the first ferromagneticlayer with respect to the oxidizing gas.

Referring now to FIG. 8 and FIG. 9, a third embodiment will bedescribed.

FIG. 8 is a drawing showing an example of the thin film configuration ofthe magnetoresistance effect element having the MgO insulator layer inthe third embodiment of the present invention. As shown in FIG. 8, inthe third embodiment, an Mg layer 66 is provided under the MgO layer 4in the thin film configuration of the magnetoresistance effect elementin FIG. 1.

FIG. 9 is a schematic diagram of the apparatus of manufacturing used inthe third embodiment. The manufacturing apparatus used in the thirdembodiment in FIG. 9 is provided newly with an Mg film forming means 67in the first film forming chamber in the manufacturing apparatus used inthe first embodiment.

The Si substrate 12 formed with SiO₂ on the surface thereof is carriedinto the first film forming chamber 21 to form the lower electrode layer9 of Ta on the substrate 12. Simultaneously, Ta spattered from the Tatarget 26 is adhered on part of the film forming chamber inner wall 37,the adhesion preventing shield 36, the partitioning plate 22 or theshutter or the like in the interior of the first film forming chamber21.

Subsequently, the substrate 12 is moved through the second film formingchamber 41 provided with the respective film forming means for PtMn andCoFe and the third film forming chamber 42 provided with the respectivemeans for Ru and CoFeB in sequence, and the substrate formed with layersup to the PtMn antiferromagnetic layer 8, the CoFe layer 6, the Ru layer5 and the first ferromagnetic layer 2 formed of CoFeB shown in FIG. 9are formed in sequence.

The respective thin film layers are formed by exhausting the air fromthe respective film forming chambers to achieve a background pressure of10⁻⁷ Pa or lower.

The substrate 12 formed with the layers up to the ferromagnetic layer 2in sequence is carried again into the first film forming chamber 21 tospatter the Mg target of the Mg film forming means 67 and form the Mglayer 66. Simultaneously, Mg spattered from the Mg target is adhered onpart of the film forming chamber inner wall 37, the adhesion preventingshield 36, the partitioning plate 22 or the shutter in the interior ofthe first film forming chamber 21. Mg is a substance whose getter effectwith respect to the oxidizing gas is large, and is a substance whosegetter effect with respect to oxygen or water or the like is large. TheMgO target of the MgO film forming means 47 is spattered to spatter theMgO layer 4 on the substrate 12 in the state of the film forming chamberas described above.

The substrate 12 formed with layers up to the MgO layer 4 is moved tothe third film forming chamber 42, where the second ferromagnetic layer3 formed of CoFeB is formed thereon. Subsequently, the substrate movesagain to the first film forming chamber 21 to form the Ta upperelectrode layer 10 thereon. Then, the substrate 12 is moved to the thirdfilm forming chamber 42 to form the Ru layer. In this manner, themagnetoresistance effect element having the thin film configurationshown in FIG. 8 is formed.

The magnetoresistance effect element formed in this manner demonstrateda preferable performance having a high MR ratio even though thethickness of the film of the MgO layer is small. Consequently, themagnetoresistance effect element with a high MR ratio was obtained evenwith a low value of RA.

In this embodiment, the substance whose getter effect with respect tothe oxidizing gas to be adhered to the surfaces of the components in thefirst film forming chamber for forming the film of MgO is large is Mg.

Since the MgO layer is formed continuously after the Mg layer, Mg isadhered to the surfaces of the components in the first film formingchamber right before forming the film of MgO, and hence it is consideredthat a high getter effect is obtained from Mg to be adhered to thesurfaces of the components in the first film forming chamber for formingthe film of MgO in this embodiment. The extent of the getter effect withrespect to the oxidizing gas varies depending on the state of thesurface of the substance. Since the Mg film is adhered to the surfacesof the components in the film forming chamber right before forming theMgO layer, the surface of the adhered Mg film is in a clean state, sothat it is considered that a higher getter effect is achieved.

In this embodiment in which the Mg layer is formed in the film formingchamber for forming the MgO layer and, in addition, the Ta layer isformed, since Mg and Ta, which are substances whose getter effects withrespect to the oxidizing gas are large, are adhered to the surfaces ofthe components in the MgO film forming chamber, the substances whosegetter effect with respect to the oxidizing gas is large may be formedfurther thickly and over a larger area, so that the higher effect isachieved. However, it does not mean that the Ta electrode layer must beformed in the MgO film forming chamber, and the same effect is achievedeven when only the Mg layer is formed in the MgO film forming chamberand the Ta layer is formed in a film forming chamber different from thefilm forming chamber for forming the MgO layer.

Referring now to FIG. 10, a fourth embodiment will be described. FIG. 10is a drawing showing a result of comparison of measured MR ratios of themagnetoresistance effect elements obtained by forming the MgO film onthe substrates 12 having the configuration shown in FIG. 1 in a state inwhich various substances are adhered to the surfaces of the componentsin the first film forming chamber for forming the MgO layer right beforeforming the MgO layer on the substrates 12.

The method of execution will be described according to an example inwhich Ti is employed as the substance to be adhered to the surfaces ofthe components in the first film forming chamber for forming the film ofMgO. The Ti film forming means is provided in the first film formingchamber in addition to the MgO film forming means, the Ta film formingmeans. The layers up to the first ferromagnetic layer 2 are laminated insequence on the substrate 12. Ta is adhered to the surfaces of thecomponents in the first film forming chamber when the Ta lower electrodelayer is formed. A step of adhering Ti in the first film forming chamber21 is inserted right before forming the MgO layer 4. In other words, themagnetoresistance effect element is formed by carrying the substrate 12having laminated with layers up to the first ferromagnetic layer 2 insequence to the first film forming chamber 21, holding the same by thesubstrate holder 29, opening the target shutter of Ti in a state inwhich the shutter 31 is closed and hence the substrate 12 is shielded,and sputtering Ti to adhere Ti to the surfaces of the film formingchamber inner wall 37, the adhesion preventing shield 36, the shutterand the partitioning plate 22. Subsequently, in this state, the MgOlayer 4 is formed on the substrate 12 in the same manner as the firstembodiment. Thereafter, the thin film is laminated in the same manner asin the first embodiment, so that the magnetoresistance effect element isformed.

In this manner, the magnetoresistance effect element is formed byforming the MgO layer in a state in which various substances are adheredto the surfaces of the components in the film forming chamber, and theMR ratios were measured. Consequently, while the MR ratio was about 50%when the MgO layer is spattered by adhering MgO, the values of MR ratioof about 70 to 130% were obtained when the MgO layer is spattered byadhering CuN, CoFe, Ru and CoFeB. It was found that the values of the MRratio obtained when spattering the MgO layer by adhering Ta, Ti, Mg, Crand Zr were as high as about 190% to 210%. As long as the substance toadhere to the surfaces of the components in the film forming chamber forforming the film of MgO is a substance whose getter effect is largerthan MgO, the effect to improve the element characteristic is achieved.Further preferably, when Ti, Cr, Zr or the like other than Ta in thefirst and second embodiments and Mg in the third embodiment of thepresent invention are selected as needed as a substance to be adhered tothe surfaces of the components in the film forming chamber for formingthe film of MgO, good effect to improve the element characteristic isachieved.

The extent of getter effect with respect to the oxidizing gas may becompared with an index of the value of the oxygen gas adsorption energyof the substance in question. On the other hands, the values of theoxygen gas adsorption energy of Ti, Ta, Mg, Cr and Zr having a high MRratio are larger than 145 kcal/mol. The substance whose value of oxygengas adsorption energy is larger than 145 kcal/mol, that is, whose gettereffect with respect to the oxidizing gas is large is adhered to thesurfaces of the components in the MgO film forming chambers, so that theoxygen gas discharged when forming the film of MgO is sufficientlygettered on the surfaces of the components to the MgO film formingchamber. Accordingly, the magnetoresistance effect element beingsubjected to less oxidation of the surface of the ferromagnetic layer ordeterioration of the film quality of the formed MgO insulator layer wasformed.

From the fact described above, it is considered that a desirable deviceperformance with a high MR ratio may be obtained even with a low RA whenthe magnetoresistance effect element is formed by forming the insulatorlayer MgO film in a state in which the substance whose getter effectwith respect to the oxidizing gas is large is adhered to the surfaces ofthe components in the film forming chamber. Therefore, even when thesubstance is a substance other than Ta, Ti, Mg, Cr and Zr in thisembodiment, it is considered that the magnetoresistance effect elementwith a high MR ratio is obtained even with a low RA by gettering theoxidizing gas such as oxygen or water discharged during the film formingprocess of the MgO layer sufficiently as long as it is a substance whosegetter effect with respect to the oxidizing gas is large. For example,the effect seems to be achieved even with Nb, Mo, W, Mn, Hf, V, B, Si,Al and Ge whose values of oxygen gas adsorption energy is larger than145 kcal/mol.

The substance adhered to the film forming chamber inner wall for formingthe film of MgO must simply includes a substance whose getter effectwith respect to the oxidizing gas is large as a main component.

When a substance whose getter effect with respect to the oxidizing gasis large is not included in the substances which constitute themagnetoresistance effect element, the substance to be adhered to thesurfaces of the components in the MgO film forming chamber may be formedby selecting a substance whose getter effect with respect to theoxidizing gas is large as needed, and providing the film forming meansfor the corresponding substance in the MgO film forming chamber.

A substance whose value of the oxygen gas adsorption energy is 145kcal/mol or higher is selected as the substance to be adhered to thesurfaces of the components in the MgO film forming chamber, so that theoxidizing gas such as oxygen or water to be discharged at the time offorming the film of MgO is sufficiently gettered on the surfaces of thecomponents in the MgO film forming chamber.

The timing to be adhered to the interior of the MgO film forming chamberis more preferably right before the formation of the MgO film, becauseit is considered that the extent of the getter effect with respect tothe oxidizing gas varies depending on the state of the surface of thesubstance, and the higher getter effect is obtained when the surface isin a clean state.

Preferably, the substance to be adhered to the interior of the MgO filmforming chamber is specifically Ta, Ti, Mg, Zr, Nb, Mo, W, Cr, Mn, Hf,V, B, Si, Al and Ge.

When the substance to be adhered in the interior of the MgO film formingchamber is a substance which forms a thin film layer which constitutesthe magnetoresistance effect element to be manufactured, the means foradhering to the interior of the MgO film forming chamber may be usedcommonly as the means for forming the thin film layer and the stepstherefor may be commonly carried out by one step, so that the apparatusmay be downsized, and the shortening of the entire process is achieved.

Referring now to FIG. 11 to FIG. 13, a fifth embodiment will bedescribed. FIG. 11 is a drawing showing an example of the configurationof a thin film of the magnetoresistance effect element having the MgOlayer which is manufactured in the fifth embodiment of the presentinvention, FIG. 12 is a cross-sectional view for explaining the internalconfiguration of the first film forming chamber in the manufacturingapparatus in the fifth embodiment of the present invention, and FIG. 13is a drawing showing an RA/MR ratio characteristic of the MgO layer ofthe magnetoresistance effect element according to the fifth embodimentof the present invention. The components having substantially the samefunction or the same configuration as those in FIG. 1, FIG. 3, FIG. 6and FIG. 8 are designated by the same reference numerals fordescription, and detailed description of the identical components isomitted.

As shown in FIG. 11, the thin film configuration of themagnetoresistance effect element having the MgO layer to be manufacturedin this embodiment includes a lower electrode portion 640 including thefirst Ta layer 61 a (film thickness: 5.0 nm), a first CuN layer 62 a(film thickness: 20 nm), a second Ta layer 61 b (film thickness: 3.0 nm)and the second CuN layer 62 b (film thickness: 20 nm), a ground layerincluding a Ta layer, 68 (film thickness: 3.0 nm) and an Ru layer 69(film thickness: 5.0 nm), an antiferromagnetic layer 80 (film thickness:7.0 nm) formed of IrMn (iridium manganese), the CoFe antiferromagneticlayer 6 (film thickness: 2.5 nm), the Ru layer 5 (film thickness: 0.85nm), the first ferromagnetic layer 2 (film thickness: 3.0 nm) formed ofCoFeB, the insulator layer 4 (film thickness: 1.0 nm) formed of MgO, thesecond ferromagnetic layer 3 (film thickness: 3.0 nm) formed of CoFeB,an upper electrode layer including a Ta layer 10 a (film thickness: 8.0nm), a Cu layer 10 c (film thickness: 30 nm) and a Ta layer 10 b (filmthickness: 5.0 nm), and the Ru layer 11 (film thickness: 7.0 nm) forpreventing oxidation laminated on a Si (silicon) substrate 120 formedwith Th-Ox (single layer heat oxidizing film) on the surface thereof.The ground layer including the Ta layer 68 and the Ru layer 69 is forcausing crystal growth of the anti-ferromagnetic layer.

The apparatus for manufacturing the magnetoresistance effect elementhaving the MgO layer according to this embodiment has substantially thesame configuration as the film forming apparatus shown in FIG. 2 andFIG. 7. However, the first film forming chamber 21 is configured asshown in FIG. 12. In the first embodiment, the description is givenabout the configuration in which the surface of the substrate holder 29is covered with the insulator formed of aluminum nitride (AlN). However,the manufacturing apparatus in this embodiment is characterized in thata substrate placing bed 290 is provided between the substrate holder 29and the substrate 12, and the substrate 12 is directly placed on thesubstrate placing bed 290. The substrate placing bed 290 must simplyhave a configuration which is able to insulate at a portion where thesubstrate holder 29 and the substrate 12 come into contact with eachother and, for example, it is also applicable to configure the substrateplacing bed 290 by spraying the insulating substance such as Al₂O₃(alumina) on the surface of the stainless steel plate or to configurethe substrate placing bed 290 by itself with the insulating substance.In this manner, the substrate 12 is brought into a state of electricallyfloated completely (floating state), that is, the substrate 12 isbrought to have a floating potential. What is essential is that thesubstrate 12 is electrically insulated from the substrate placing bed290 and the substrate holder 29. The surface of the substrate holder 29by itself according to this embodiment does not have to be covered withthe insulator.

Here, bringing the substrate 12 to have the floating potential, forexample, is achieved by means such as insulating the substrate placingbed 290 from the substrate holder 29, or insulating the substrate holder29 from the ground in addition to insulating the substrate 12 from thesubstrate placing bed 290 as described above. What is essential is thatthe substrate 12 is insulated from the ground at any portion between thesubstrate 12 and the ground. There are various methods of insulatingsuch as interposing an insulating substance, configuring the componentssuch as the substrate placing bed 290 or the substrate holder 29 byitself with the insulating substance, configuring only the portion to beinsulated (portion to come into contact) with an insulating substance,or keeping the portions to be insulated from each other apart from eachother.

The method of manufacturing the magnetoresistance effect element havingthe MgO layer in this embodiment is characterized in that the substrateholder 29 is insulated from the substrate 12, and the MgO layer 4 isformed in the state in which the substrate 12 is electrically floatedcompletely (floating state) as described above. The step of forming theMgO layer 4 on the substrate 12 in the state in which the substancewhose getter effect with respect to the oxidizing gas is large (Ta orthe like) is adhered to the surface of the components in the interior ofthe first film forming chamber 21 for forming MgO layer 4 and other filmforming steps are the same as that in the embodiment which is alreadydescribed, so that detailed description is omitted.

When spraying Al₂O₃ on the surface of the stainless steel panel toconfigure the substrate placing bed 290, the substrate 12 is broughtinto the floating state by spraying the Al₂O₃ to a thickness of about0.2 mm. The substrate 12 is also brought into the floating state byconfiguring the substrate placing bed 290 by itself by an AlN panel(thickness of about 14 mm) as the insulating substance. Therefore, themagnetoresistance effect element having the MgO layer is manufactured insuch the configuration, and the RA/MR ratio characteristics of the MgOlayer of the magnetoresistance effect element are compared (FIG. 13). InFIG. 13, (I) represents the characteristic when the substrate placingbed 290 formed of the stainless steel panel is used, (II) represents thecharacteristic when the substrate placing bed 290 on which Al₂O₃ issprayed by a thickness of about 0.2 mm on the surface of the stainlesssteel panel is used, and (III) represents the characteristic when thesubstrate placing bed 290 formed of an AlN panel of a thickness of about14 mm is used. The reason when AlN is selected in the case of (III) isbecause its coefficient of thermal conductivity is high.

As shown in FIG. 13, for example, in the case of (I) where the substrateplacing bed 290 formed of the stainless steel panel is used with an RAof 10 Ω-μm², the MR ratio is lowered to about 50%. However, in the case(II) where the substrate placing bed 290 obtained by spraying Al₂O₃ onthe surface of the stainless steel panel is used and in the case (III)where the substrate placing bed 290 formed of AlN panel is used, an MRratio as high as 200% or more was achieved. Therefore, by forming thefilm by placing the substrate 12 on the substrate holder 29 via theinsulating substance (the substrate placing bed 290) as in the firstembodiment, the extent of lowering of the MR ratio is small even in thelow RA area, so that a higher MR ratio is obtained in comparison withthe case in the related art, so that achievement of both the low RA andthe high MR ratio, which is considered to be difficult in the relatedart, may be realized.

As is clear from the point where the value of Ra is 5 Ω-μm2, the higherMR ratio is obtained in the case in which the case (III) where thesubstrate placing bed 290 formed of AlN panel is used than in the case(II) where the substrate placing bed 290 obtained by spraying Al₂O₃ onthe surface of the stainless steel panel. Therefore, the subject toachieve low RA and high MR ratio is realized further preferably. Thethin film configuration (FIG. 11) of the magnetoresistance effectelement manufactured according to the present embodiment is differentfrom the thin film configuration (FIG. 1, FIG. 6, FIG. 8) of themagnetoresistance effect element in the respective embodiments describedalready above in the antiferromagnetic layer 80 formed of IrMn (iridiummanganese) and the ground layer (the Ta layer 68 and the Ru layer 69) orthe like. However, the same results as described above may be obtainedby bringing the substrate 12 into the floating state in the apparatus orthe method of manufacturing the magnetoresistance effect element havingthe thin film configuration shown in the respective embodiments as well.

Referring now to FIG. 14, a sixth embodiment will be described. FIG. 14is a cross-sectional view for explaining the internal structure of thefirst film forming chamber of the manufacturing apparatus in the sixthembodiment of the present invention. The components having substantiallythe same function or the same configuration as those in FIG. 3 and FIG.12 are designated by the same reference numerals for description, anddetailed description of the identical components is omitted.

In the fifth embodiment described above, the film forming apparatus orthe film forming method for forming the MgO layer 4 on the substrate 12in a state in which the substance whose getter effect with respect tothe oxidizing gas is large (Ta or the like) is adhered to the surfacesof the components in the interior of the first film forming chamber 21for forming the MgO layer 4 has been described. However, the inventionis not necessarily limited to be the state in which the above-describedsubstance is adhered. In other words, the sixth embodiment ischaracterized in that the MgO layer 4 is formed in a state in which thesubstrate holder 29 is insulated from the substrate 12 and the substrate12 is electrically floating completely (the state at the floatingpotential) without adhering the above-described substance (Ta or thelike) to the surfaces of the components in the interior of the firstfilm forming chamber 21 for forming the MgO layer 4. Therefore, in themanufacturing apparatus in this embodiment, the same substrate placingbed 290 which is the same as the substrate placing bed 290 in the fifthembodiment described above is provided between the substrate holder 29and the substrate 12, and the substrate 12 is directly placed on thesubstrate placing bed 290. In this embodiment, since the above-describedsubstance (Ta or the like) is adhered to the surface of the componentsin the interior of the first film forming chamber 21 for forming the MgOlayer 4, the interior of the first film forming chamber 21 must simplybe arranged only for MgO as a target as shown in FIG. 14, and it is notspecifically necessary to provide the Ta 26 as a target, the targetmounting portion 25, the partitioning plate 22, the shutters 27 and 28(see FIG. 12). Consequently, the extent of lowering of the MR ratio issmall even in the low RA area as shown in FIG. 13, and a larger MR ratiothan in the related art is obtained.

Referring now to FIG. 15 and FIG. 16, a seventh embodiment will bedescribed. FIG. 15 is a drawing for showing a configuration of theportion near the substrate holder in the manufacturing apparatus in theseventh embodiment of the present invention in which (a) is a drawingshowing a state in which a mask and the substrate are in contact witheach other, (b) is a drawing showing a state in which the mask and thesubstrate are apart from each other, and FIG. 16 is a drawing showingthe RA/MR ratio characteristic of the MgO layer of the magnetoresistanceeffect element according to this embodiment. The components havingsubstantially the same function and the same configuration as those inFIG. 3, and FIG. 12 are designated by the same reference numerals fordescription, and detailed description of the identical components isomitted.

In general, when forming the film in a state in which the substrate isheld by the substrate holder, the metallic mask for covering theperipheral portion of the substrate for holding the same is employed inorder to prevent the film from being formed on the back side of thesubstrate (the side which comes into contact with the substrate holder)by film forming particles running to the backside thereof (see FIG. 15(a), reference numeral 295). As regards this point, this embodiment isadapted to carry out the step of forming the MgO layer 4 in a state ofproviding the substrate placing bed 290 described above between thesubstrate holder 29 and the substrate 12, placing the substrate 12directly on the substrate placing bed 290, and keeping a metallic mask295 apart from the substrate 12 in the state in which the substrate 12is at the floating potential as shown in FIG. 15( b). It is alsopossible to bring the substrate 12 to a state of being at the floatingpotential by other methods described above. The mask 295 and thesubstrate 12 must simply be kept apart from each other by a distancewhich is able to prevent spatter particles from running to the backsideof the substrate 12, and for example, is set to 0.5 mm. In this manner,by bringing the mask 295 and the substrate 12 apart from each other, themask 295 and the substrate 12 are brought into the electricallyinsulated state.

In the present invention, the mask is a component for covering theperipheral portion of the substrate for preventing the film from beingformed by the film forming particles running to the backside of thesubstrate in a case of carrying out the film forming process on thesubstrate.

In a step of forming the MgO layer 4, the magnetoresistance effectelement having the MgO layer is manufactured on the basis of therespective cases where the mask 295 is brought into contact with theperipheral portion of the substrate 12 as shown in FIG. 15(a), and wherethe mask 295 and the substrate 12 are brought apart from each other asshown in FIG. 15( b), and the RA/MR ratio characteristics of the MgOlayer of the magnetoresistance effect element having the MgO layer arecompared (FIG. 16). In FIG. 16, solid triangles (▴) represent thecharacteristics when the mask 295 is brought into contact with theperipheral portion of the substrate 12, and solid circles (•) representa characteristic in the case in which the mask 295 and the substrate 12are brought apart from each other.

For example, a higher MR ratio is obtained in the case (•) in which themask 295 and the substrate 12 are brought apart from each other than thecase (solid triangle) in which the mask 295 and the substrate 12 arebrought into contact with each other at a point where the RA is 5 Ω-μm²,and as a whole, the subject to achieve both low RA and high MR ratio isrealized further preferably in the case (•) in which the mask 295 andthe substrate 12 are brought apart from each other. Therefore, it isconsidered that the mask 295 and the substrate 12 are brought into theelectrically insulated state by bringing the metallic mask 295 and thesubstrate 12 apart from each other, and the electric current isprevented from flowing to the MgO layer during the formation of the MgOfilm and, consequently, prevention of deterioration of the film qualityof the MgO layer and deterioration of the characteristic of themagnetoresistance effect element are achieved.

In this embodiment, the mask 295 and the substrate 12 are brought intothe electrically insulated state by bringing the mask 295 and thesubstrate 12 apart from each other. However, for example, by forming themask 295 by itself of an insulating substance, the state in which themask 295 and the substrate 12 are electrically insulated may be achievedeven when the substrate 12 and the mask 295 are in contact with eachother as shown in FIG. 15( a), so that the same effects as describedabove are achieved.

Although the embodiments from the first embodiment to the seventhembodiment of the present invention have been described referring to theattached drawings thus far, the present invention is not limited to theembodiments shown above, and various modifications may be made withinthe technical scope understood from the description in claims.

For example, although the film forming apparatus in the embodiments hasbeen described as an apparatus having the three film forming chambers,the invention is not limited thereto. Although the apparatus of thepresent invention is described as an apparatus having two or three filmforming means in the film forming chamber, the invention is not limitedthereto. The apparatus of the present invention is not limited to theshape of the film forming chamber in the apparatus shown in theembodiments.

In the apparatus in the embodiments, the components in the film formingchamber for adhering the substance whose getter effect with respect tothe oxidizing gas such as oxygen or water is large have been describedas the film forming chamber inner wall, the adhesion preventing shield,the partitioning panel or the shutter, they are not limited thereto.What is important is adhesion to the surfaces of the components in theinterior of the film forming chambers, and it may be otherconfigurations.

Although the method of forming the respective layers of themagnetoresistance effect element has been described as the method on thebasis of the spattering, other film forming methods such as depositionor the like are also applicable, and the film forming method is notspecifically limited.

1. A method of manufacturing a magnetoresistance effect element havingan MgO layer between a first ferromagnetic layer and a secondferromagnetic layer comprising: a step of forming the firstferromagnetic layer; a step of forming the MgO layer; and a step offorming the second ferromagnetic layer in this order, characterized inthat the step of forming the MgO layer is carried out in a film formingchamber including a component having a substance whose getter effectwith respect to oxidizing gas is larger than MgO adhered to the surfacethereof.
 2. The method of manufacturing a magnetoresistance effectelement according to claim 1, characterized in that the film formingchamber for forming the MgO layer includes at least one film formingmeans for a substance whose getter effect with respect to the oxidizinggas is larger than MgO, and adhesion of the substance whose gettereffect with respect to the oxidizing gas is larger than MgO to thecomponent is carried out by the at least one film forming means.
 3. Themethod of manufacturing a magnetoresistance effect element according toclaim 1 or claim 2, characterized in that the substance whose gettereffect with respect to the oxidizing gas is larger than MgO includes atleast one element which is included in the substance which constitutesthe magnetoresistance effect element.
 4. A method of manufacturing amagnetoresistance effect element having an MgO layer between a firstferromagnetic layer and a second ferromagnetic layer comprising: a stepof forming the first ferromagnetic layer, a step of forming the MgOlayer, and a step of forming the second ferromagnetic layer in thisorder, characterized in that the step of forming the MgO layer iscarried out in a film forming chamber including a component having asubstance whose getter effect with respect to oxidizing gas is largerthan the substance which constitutes the first ferromagnetic layeradhered to the surface thereof.
 5. The method of manufacturing amagnetoresistance effect element according to claim 4, characterized inthat the film forming chamber for forming the MgO layer includes atleast one film forming means for a substance whose getter effect withrespect to the oxidizing gas is larger than the substance whichconstitutes the first ferromagnetic layer, and adhesion of the substancewhose getter effect with respect to the oxidizing gas is larger than thesubstance which constitutes the first ferromagnetic layer to thecomponent is carried out by the film forming means.
 6. The method ofmanufacturing a magnetoresistance effect element according to claim 4 orclaim 5, characterized in that the substance whose getter effect withrespect to the oxidizing gas is larger than the substance whichconstitutes the first ferromagnetic layer includes at least one elementwhich is included in the substance which constitutes themagnetoresistance effect element.
 7. A method of manufacturing amagnetoresistance effect element having an MgO layer between a firstferromagnetic layer and a second ferromagnetic layer comprising: a stepof forming the first ferromagnetic layer, a step of forming the MgOlayer, and a step of forming the second ferromagnetic layer in thisorder, characterized in that the step of forming the MgO layer iscarried out in a film forming chamber including a component having asubstance whose getter effect with respect to oxidizing gas the largestamong substances which constitute the magnetoresistance effect elementadhered to the surface thereof.
 8. A method of manufacturing amagnetoresistance effect element having an MgO layer between a firstferromagnetic layer and a second ferromagnetic layer comprising: a stepof forming the first ferromagnetic layer, a step of forming the MgOlayer, and a step of forming the second ferromagnetic layer in thisorder, characterized in that the step of forming the MgO layer iscarried out in a film forming chamber having a component including acomponent having a substance whose value of oxygen gas adsorption energyis 145 kcal/mol or higher adhered to the surface thereof.
 9. A method ofmanufacturing a magnetoresistance effect element having an MgO layerbetween a first ferromagnetic layer and a second ferromagnetic layercomprising: a step of forming the first ferromagnetic layer, a step offorming the MgO layer, and a step of forming the second ferromagneticlayer in this order, characterized in that the step of forming the MgOlayer is carried out in a film forming chamber having a componentincluding metal or a semiconductor including at least one of Ta, Ti, Mg,Zr, Nb, Mo, W, Cr, Mn, Hf, V, B, Si, Al and Ge adhered to the surfacethereof.
 10. The method of manufacturing a magnetoresistance effectelement according to claim 1, claim 2, claim 4, claim 5, claim 7, claim8 or claim 9, characterized in that the step of forming the MgO layerforms the MgO layer by a spattering method.
 11. A method ofmanufacturing a magnetoresistance effect element using an apparatushaving a plurality of film forming chambers including a first filmforming chamber connected to a carrier chamber via a valve being capableof transferring substrates through the plurality of film formingchambers without impairing vacuum, comprising: a first step for adheringa substance whose getter effect with respect to oxidizing gas is largerthan MgO to the surface of a component in the first film formingchamber; a third step carried out after the first step for forming anMgO layer on the substrate in the first film forming chamber; and asecond step for carrying out from a next step of the first step to astep before the third step in the film forming chamber other than thefirst film forming chamber, characterized in that the first step, thesecond step and the third step are carried out continuously in thisorder.
 12. A method of manufacturing a magnetoresistance effect elementusing an apparatus having a plurality of film forming chambers includinga first film forming chamber connected to a carrier chamber via a valvebeing capable of transferring substrates through the plurality of filmforming chambers without impairing vacuum, comprising: a first step ofadhering a substance whose value of oxygen gas adsorption energy is 145kcal/mol or higher to the surface of a component in the first filmforming chamber; a third step carried out after the first step forforming an MgO layer on the substrate in the first film forming chamber;and a second step for carrying out from a next step of the first step toa step before the third step in the film chamber other than the firstfilm forming chamber, characterized in that the first step, the secondstep and the third step are carried out continuously in this order. 13.A method of manufacturing a magnetoresistance effect element using anapparatus having a plurality of film forming chambers including a firstfilm forming chamber connected to a carrier chamber via a valve beingcapable of transferring substrates through the plurality of film formingchambers without impairing vacuum, comprising: a first step for adheringmetal or a semiconductor including at least one of Ta, Ti, Mg, Zr, Nb,Mo, W, Cr, Mn, Hf, V, B, Si, Al and Ge to the surface of a component inthe first film forming chamber; a third step carried out after the firststep for forming an MgO layer on the substrate in the first film formingchamber; and a second step for carrying out from a next step of thefirst step to a step before the third step in the film forming chamberother than the first film forming chamber, characterized in that thefirst step, the second step and the third step are carried outcontinuously in this order.
 14. The method of manufacturing amagnetoresistance effect element according to any one of claims 11 to13, characterized in that the first step adheres the substance whosegetter effect with respect to the oxidizing gas is large to the surfaceof the component in the first film forming chamber and, simultaneously,forms a film on the substrate.
 15. The method of manufacturing amagnetoresistance effect element according to any one of claims 11 to13, characterized in that the first step is carried out in parallel withthe step of forming a film on the substrate in the film forming chamberother than the first film forming chamber.
 16. The method ofmanufacturing a magnetoresistance effect element according to any one ofclaims 11 to 13, characterized in that the third step forms the MgOlayer by a spattering method.
 17. A method of manufacturing amagnetoresistance effect element using an apparatus having a pluralityof film forming chambers including a first film forming chamberconnected to a carrier chamber via a valve being capable of transferringsubstrates through the plurality of film forming chambers withoutimpairing vacuum, comprising: a step of transferring the substrate tothe first film forming chamber, spattering Mg in the first film formingchamber and forming an Mg layer on the substrate and, simultaneously,adhering Mg to the surface of a component in the first film formingchamber; and a subsequent step of forming an MgO layer in the first filmforming chamber.
 18. An apparatus for manufacturing a magnetoresistanceeffect element, characterized in that a film forming chamber for formingan MgO layer includes means for adhering a substance whose getter effectwith respect to oxidizing gas is larger than MgO to the surface of acomponent in the film forming chamber provided therein.
 19. An apparatusof manufacturing a magnetoresistance effect element having an MgO layerbetween a first ferromagnetic layer and a second ferromagnetic layercomprising: means for adhering a substance whose getter effect withrespect to oxidizing gas is larger than the substance which constitutesa first ferromagnetic layer to the surface of a component in the filmforming chamber in the film forming chamber for forming the MgO layer.20. The apparatus of manufacturing a magnetoresistance effect elementaccording to claim 18 or claim 19, characterized in that the substancewhose getter effect with respect to the oxidizing gas is large is asubstance having the largest getter effect with respect to the oxidizinggas among the substances which constitute the magnetoresistance effectelement.
 21. An apparatus of manufacturing a magnetoresistance effectelement comprising: means for adhering a substance whose value of oxygengas adsorption energy is 145 kcal/mol or higher to the surface of acomponent in the film forming chamber in the film forming chamber forforming an MgO layer.
 22. An apparatus of manufacturing amagnetoresistance effect element comprising: means for adhering metal ora semiconductor including at least one of Ta, Ti, Mg, Zr, Nb, Mo, W, Cr,Mn, Hf, V, B, Si, Al and Ge to the surface of a component in the filmforming chamber in the film forming chamber for forming an MgO layer.23. The apparatus of manufacturing a magnetoresistance effect elementaccording to claim 18, claim 19, claim 21 or claim 22, comprising: aplurality of film forming chambers including the film forming chamberfor forming the MgO layer connected to a carrier chamber via a valvebeing capable of transferring substrates through the plurality of filmforming chambers without impairing vacuum.
 24. The apparatus ofmanufacturing a magnetoresistance effect element according to any one ofclaim 18, claim 19, claim 21 or claim 22, characterized in that a targetof MgO is provided in the film forming chamber for forming the MgOlayer, and an electric power supply unit for supplying an electric powerto the target is provided.
 25. A method of manufacturing amagnetoresistance effect element having an MgO layer between a firstferromagnetic layer and a second ferromagnetic layer, comprising: a stepof forming the first ferromagnetic layer, a step of forming the MgOlayer, and a step of forming the second ferromagnetic layer,characterized in that the step of forming the MgO layer is carried outin a state in which a substrate is at a floating potential.
 26. A methodof manufacturing a magnetoresistance effect element having a substrate,a first ferromagnetic layer, a second ferromagnetic layer and an MgOlayer formed between the first ferromagnetic layer and the secondferromagnetic layer, comprising: a step of forming the firstferromagnetic layer on the substrate; a step of forming the MgO layer;and a step of forming the second ferromagnetic layer, characterized inthat the step of forming the MgO layer is carried out by placing thesubstrate on a substrate placing bed having a portion which comes intocontact with the substrate formed of the insulating substance.
 27. Themethod of manufacturing a magnetoresistance effect element according toclaim 26, characterized in that the substrate is placed on the substrateplacing bed on which the insulating substance is sprayed.
 28. The methodof manufacturing a magnetoresistance effect element according to claim26, characterized in that the substrate is placed on the substrateplacing bed formed of an insulating substance.
 29. The method ofmanufacturing the magnetoresistance effect element according to any oneof claim 26 to claim 28, characterized in that the step of forming theMgO layer is carried out in a state in which a mask is arranged on aperipheral portion of the substrate so as to be apart from thesubstrate.
 30. A method of manufacturing a magnetoresistance effectelement having an MgO layer between a first ferromagnetic layer and asecond ferromagnetic layer, comprising: a step of forming the firstferromagnetic layer, a step of forming the MgO layer and a step offorming the second ferromagnetic layer, characterized in that the stepof forming the MgO layer is carried out in a state in which thesubstrate and a substrate holding holder for holding the substrate areelectrically insulated.
 31. The method of manufacturing amagnetoresistance effect element according to claim 30, characterized inthat the step of forming the MgO layer is carried out in a state inwhich a mask electrically insulated from the substrate is arranged inthe peripheral portion of the substrate.
 32. An apparatus ofmanufacturing a magnetoresistance effect element having an MgO layerbetween a first ferromagnetic layer and a second ferromagnetic layercomprising: means for bringing a substrate into a state of being at afloating potential in a film forming chamber for forming the MgO layer.33. An apparatus of manufacturing a magnetoresistance effect elementhaving an MgO layer between a first ferromagnetic layer and a secondferromagnetic layer comprising: means for electrically insulating asubstrate and a substrate holder for holding the substrate in a filmforming chamber for forming the MgO layer.